This invention relates to a method of treating oil/water emulsions and solutions in waste streams by contacting the emulsion or solution with a salt, a synthetic polymer, flocculant and a demulsifying agent.
Numerous solutions have been proposed for the problem of disposing of waste water containing soluble or insoluble oils, oil-like substances and other organic impurities, for example, greases, soaps, and detergents, which may bing tightly with the water in an emulsions. These waste streams are often generated by factories, refineries, and even laundries and car washes. In addition to the aforementioned organic substances, the waste water may further contain heavy metals such as zinc, chromium, copper and cadmium. All of the aforementioned substances must be greatly reduced or essentially removed from the waste water before the water may be disposed of into the environment.
The solutions set forth in the prior art to the problem of disposing of the aforementioned impure waste water include various processes whereby substances are added to the waste water to cause the oil and the other impurities to resolve or be separated into a separate phase from the water so that the water may be easily separated from the impurities. The substances used in the prior art include various flocculants, both natural and synthetic, salts, such as calcium chloride, and demulsifying agents, such as sulfuric acid. However, these prior art processes themselves have numerous problems for example, their cost effectiveness, the adequacy of the separation and the complexity of the treatment process.
In addition to the above problems, where ultra or micro filtration is employed to purify oily waste water streams, the process of separation is often incomplete and, even worse, leaves the oily substances even more tightly bound in emulsion to the water. Consequently, the water output from ultra or micro filtration, referred to as "concentrates", are extremely high in water and contain tightly bound impurities. This is especially common with concentrates from commercial laundry waste streams which often contain solvents and strong detergents. These concentrates are quite expensive to dispose of, whether by incineration or other means.
Bearing in mind these and other problems of the prior art, it is an object of the present invention to provide an improved process for resolving or spliting oil/water emulsions and solutions.
It is another object of the present invention to provide a process for spliting tightly bound emulsion concentrates which are produced by ultra or micro filtration.
It is a further object of the present invention to provide a process for resolving oil/water emulsions and solutions which is easily operable, uses relatively low cost components, and produces a separate purified water phase.